I doubt we'll ever need screens with higher resolution thant the 327 pixels per inch that the new iPhone has. Even with reading glasses, I'm not even near able to see everything it can resolve. If I use a loupe, lots of new details resolve, for example in the tiny icons inside a folder icon.
Are there really people with eyes so good? If so, I envy them.
Apropos the folders, I like them. I found the old system of many apps strewed over many screens to be highly confusing. Now I have reduced all my apps into three folders on one screen, and three or four icons in the dock. (Maybe it's not called a Dock on the iOS, but who gives a flying f**k, it's the same thing, just like the Task Bar on Windows.)
BTW, I'm very surprised to hear that iPod Touches are outselling iPhones! To me, the iPod Touch is a weird compromise: it's not a phone, it's not a tablet, and it's not a good iPod (the controls are much more finicky than the classic iPod, much more difficult to control precisely).
Steve Jobs seemed a bit surprised himself, when he mentioned it.